In context of overlay "Buildings" – Indoor Stairwell – osm.org/way/333605981 via StreetComplete 58.2:

Außerliegende Treppe an dem Gebäude.

Unable to answer "What diameter is specified on the sign for this fire hydrant?" – Fire Hydrant – osm.org/node/11565571470 via StreetComplete 58.2:

Does not feature a H in the top row.

Attached photo(s):
https://westnordost.de/p/232380.jpg

Unable to answer "This shop has been vacant. What’s here now?" – osm.org/node/8656071294 via StreetComplete 57.1:

There is no shop any more.
(There was a temporary Corona test station.)

Unable to answer "What type of shop is this?" for osm.org/node/5958134499 via StreetComplete 52.0:

Second Hand

Unable to answer "Are these opening hours still correct?" for osm.org/node/643462941 via StreetComplete 53.0:

Öffnungszeiten ändern sich pro Semester. Teilweise auch zwischendurch.
Die Bibliothek ist länger offen aber aber einer gewissen Uhrzeit nicht mehr besetzt.

Attached photo(s):
https://westnordost.de/p/152530.jpg